Technical Field
The instant disclosure relates to a fingerprint identification device and manufacturing method thereof, in particular a fingerprint identification device utilizing the wafer level package (WLP) technique.
Related Art
With the continuous advancement of technology, biometric identification schemes such as fingerprint, voiceprint, iris, and retina are gradually being applied widely to personal identification and authentication. Since fingerprint characteristic information requires less memory space relative to other biological characteristic information, and based on the combined consideration of biological characteristic information with regards to user friendliness, security, and identification efficiency, fingerprint identification has become the mainstream method of biological identification technology. Consequently, many products in the market such as laptop computers, tablet computers, and mobile phones, are equipped with fingerprint identification capability to enhance user security.
To date, capacitive fingerprint identification may be categorized into active and passive types. With the active capacitive fingerprint identification technique, fingerprint identification devices utilize standalone metal rings for contacting the user's fingers, such that the fingers export pulse wave signals. The pulse wave signals are received by the finger touching area, and identified to obtain the fingerprint information. However, after each fingerprint identification device has been made, these metal rings for the known active capacitive fingerprint identification devices must be individually recessed into the fingerprint identification device, which makes the overall manufacturing process more complex and increases the manufacturing cost.
With the passive capacitive fingerprint identification technique, fingerprint information is obtained via parasitic capacitance of each sensing element in a fingerprint sensing chip and difference in electrical charge of the sensing capacitance formed between the user's fingers. However, since sensing elements with a large area are required for the known passive capacitive fingerprint identification chip, the chip itself takes up a large area that also increases the manufacturing cost.
Consequently, how to simplify the manufacturing process of fingerprint identification devices and lower its manufacturing cost are important issues to consider for persons having ordinary skill in the art.